Low viscosity functional fluids

ABSTRACT

Low viscosity functional fluids are described which comprise glycols and an additive package that includes a fatty acid and a phosphate ester, such as a phosphate ester of an alkyl, alkenyl, or aryl alcohol. The fluids are particularly well-suit for use as DOT 3 or DOT 4 brake fluids and provide robust lubricity and corrosion inhibition.

TECHNICAL FIELD

The present application claims the benefit of the filing date of U.S.application Ser. No. 61/112,466, filed Nov. 7, 2008, which is herebyincorporated by reference for all purposes.

This disclosure relates to low viscosity functional fluids which areuseful in a variety of applications, and in particular, as brake fluids.

BACKGROUND

Newly developed equipment such as electronic or automated anti-lockbraking systems, stability control systems and regenerative brakingsystems have created a need for high performance hydraulic fluids (e.g.,brake fluids) having appropriate physical and performance properties. Inparticular, there is a strong demand for high performance brake fluidshaving high lubricity to reduce or eliminate brake noise, whileimproving the life of the brake by reducing corrosion. The U.S.Government has developed standards that govern the designation andcertification of functional fluids that are used as brake fluids using asystem of DOT (Department of Transportation) designations (e.g., DOT 3,DOT 4, DOT 5.1, etc.). The standards are embodied in Federal MotorVehicle Safety Standard 116 (“FMVSS 116”). In addition, certainstandard-setting organizations such as the Society of AutomotiveEngineers (“SAE”) and the International Standards Organization (“ISO”)have developed their own standards and certifications for brake fluids.SAE Standard J1703 covers non-petroleum brake fluids with certainphysical properties, including those shown below. SAE Standard J1704covers “borate ester based brake fluids” that achieve a level ofperformance above those of the SAE J1703 standard. Similarly, ISO 4925provides a number of brake fluid designations that are used outside ofthe United States, such as “Class 3,” “Class 4,” “Class 5-1,” and “Class6.”

FMVSS 116, SAE J1703, SAE J1704, and ISO 4925 provide stringent physicalproperty and performance requirements particularly with respect tominimum dry equilibrium reflux boiling point (ERBP), minimum wetequilibrium boiling point (WERBP), and maximum low temperature (−40° C.)viscosity. They also require maintaining adequate resistance tocorrosion, stability and other specified physical properties such as pH,reserve alkalinity, rubber swell, etc. The entirety of SAE J1703 (Rev.April 2004) and J1704 (Rev. April 2004) and FMVSS 116 are herebyincorporated by reference.

The most current standards for brake fluids are set forth below:

TABLE 1 DOT 3, DOT 4 and DOT 5 Brake Fluid Standards FMVSS 116, SAEFMVSS FMVSS 1703, ISO, 116, SAE 116, ISO Standard 4925 1704 ISO 49254925 ISO 4925 Classification DOT 3 DOT 4 DOT 5.1 (FMVSS, SAE)Classification Class 3 Class 4 Class 5.1 Class 6 (ISO) ERBP Min 205° C.Min 230° C. Min 205° C. Min 260° C. Min 250° C. Wet ERBP (3.5% Min 140°C. Min 155° C. Min 155° C. Min 180° C. Min 165° C. water per FMVSS 116)KINEMATIC Max. 1500 cSt Max. 1800 cSt Max. 1500 cSt Max. 900 cSt Max.750 cSt VISCOSITY @ −40° C.

One exemplary solution to providing such desirable functional fluids wasintroduced in commonly owned U.S. Patent Application Publication2007/0027039, entitled “Low Viscosity Functional Fluids”, andincorporated herein by reference for all purposes. Advantageously, ithas been found that the desirable properties of these prior functionalfluids can further be improved, in particular in the areas of lubricityand corrosion resistance. Moreover, it has been discovered that suchimprovements can be achieved without incurring significant cost. Evenfurther, it may be possible to actually reduce cost through the use ofnew ingredients as well as prior ingredients or other alternativeingredients of such functional fluids.

Many newer brake system master cylinders include a plastic lining whichis engaged by the rubber cup of the master cylinder piston when thebrakes are actuated. It has been found that many known brake fluidsprovide insufficient lubricity in such applications, resulting inexcessive noise and wear. Through the use of modified functional fluids,it may be possible to reduce such noise and wear.

FMVSS 116, J1703, J1704, and ISO 4925 each include corrosionspecifications based on defined test procedures in which metal strips ofvarious metals are submerged in a mixture of 5 percent water (by volume)and the brake fluid for a specified time (120 hours) at a specifiedtemperature (100° C.). It has been found that the FMVSS 116, J1703,J1704, and ISO 4925 standards do not reliably reproduce the actual roadconditions to which many brake fluids are subjected, especially forroads in the northern climates of the U.S. which are frequently saltedin the winter to control ice accumulation. As a result, it has beenproposed to modify the test procedures used to evaluate corrosion byadding a chloride salt (e.g., NaCl) to the water/brake fluid mixture.However, current brake fluids are not able to provide the level ofcorrosion resistance required for DOT3, DOT 4, J1703, J1704 and ISO 4925fluids when subjected to this modified test. For example, Shannon, U.S.Pat. No. 6,558,569 and Park U.S. Pat. No. 6,339,050 describe DOT 4 brakefluids comprising alkyl glycol borate esters, alkyl glycols, and acorrosion inhibitor package. However, they do not address the issue ofbrake fluid contamination with salt water and provide no indication thatthe disclosed fluids could meet the SAE J1703/J1704 or ISO 4925corrosion standards when subjected to a salt water environment. Thus, aneed has arisen for a functional fluid which addresses the foregoingissues.

SUMMARY

A fluid composition is provided which comprises at least one glycol andan additive package comprising at least one fatty acid and at least onephosphate ester. In certain exemplary embodiments, the at least onefatty acid is an aliphatic carboxylic acid having at least 2, preferablyat least 5, more preferably at least 10, and even more preferably atleast 15 carbon atoms. In other exemplary embodiments, the at least onefatty acid has no more than 35 preferably no more than 30, and even morepreferably no more than 25 carbon atoms. In further exemplaryembodiments, the fatty acid is monounsaturated. The fatty acids in theadditive package are generally present in an amount that is at leastabout 0.01 percent, preferably at least about 0.04 percent, and morepreferably at least about 0.08 percent by weight of the fluidcomposition. The fatty acids are generally present in an amount that isno greater than about 0.4 percent, more preferably no greater than about0.2 percent, and even more preferably no greater than about 0.15 percentby weight of the fluid composition.

The phosphate ester is generally a mono, di- or tri-ester of an alcoholand phosphoric acid (H₃PO₄). The alcohol preferably has the formulaR₁—R₂—OH, wherein R₁ is a substituted or unsubstituted alkyl, alkenyl,or aryl group having at least 2, more preferably at least 3, even morepreferably at least 4, and still more preferably at least 6 carbonatoms. R₁ has no more than 30, preferably no more than 28, even morepreferably no more than 26, and still more preferably no more than 24carbon atoms. R₂ is preferably an alkyl or an alkoxy group havingbetween two and six carbon atoms. In one exemplary embodiment, R₂ is anethoxy group (—O—CH₂—CH₂—).

A fluid composition is also provided which comprises at least one glycoland an additive package, wherein when the fluid is applied between afirst surface comprising a glass fiber/polyamide 66 composite and asecond surface comprising an 80 Shore A hardness EPDM rubber, thecoefficient of friction is less than about 0.07 after 100 seconds ofsliding engagement between the first and second surfaces. In certainexemplary embodiments, the coefficient of friction is less than about0.03 after about 100 seconds of sliding engagement. In other exemplaryembodiments, the fluid has an equilibrium reflux boiling point of atleast about 230° C. In other exemplary embodiments, the fluid has akinematic viscosity of not more than about 1800 cSt at −40° C. Incertain illustrative applications, the fluid is used as a mastercylinder lubricant.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plot of frictional data for a first low viscosity, glycolbase fluids and two modified versions of the fluid which include oleicacid and/or a phosphate ester; and

FIG. 2 is a plot of frictional data for a second low viscosity, glycolbase fluid and two modified versions of the fluid which include varyingamounts of a phosphate ester.

DETAILED DESCRIPTION

This disclosure relates to functional fluids comprising one or moreglycols and an additive package that includes at least one fatty acidand a phosphate ester. The fatty acid and phosphate ester are preferablypresent in an amount that is effective to aid in the lubricationfrictionally engaged surfaces and to inhibit corrosion when the fluid iscontaminated with salt water.

The functional fluids described herein generally comprise greater thanabout 20 percent by weight of total glycols, more preferably greaterthan about 40 percent by weight of total glycols, and even morepreferably greater than about 60 percent by weight of total glycols.Total glycol amounts of greater than about 70 percent are even morepreferred, and total glycol amounts of greater than about 80 percent byweight are especially preferred. The total amount of glycols ispreferably less than 100 percent by weight of the total functional fluidcomposition and is preferably no greater than about 99 percent by weightof the total fluid composition.

The glycol component can be formed partially, substantially entirely (atleast 90 percent or at least 95 percent by weight) or entirely of one,two, three or more glycols, polyglycols, or both. Preferably the glycolsor polyglycols of the glycol component have the formula of EQUATION I:

with repeat unit:

Each of R₁, R₂, R₃, R₄, R₅ is either hydrogen (H) or an alkyl groupcontaining 1 to 8 or more carbon atoms or mixtures thereof such as onedisclosed in Provisional Application Ser. No. 60/976,010 (filed Sep. 28,2007) entitled “Functional Fluid Composition”, which is herebyincorporated by reference for all purposes. It is preferable that R₁ bean alkyl group containing 1 to 8 carbon atoms such that the glycol orpolyglycol is an alkoxy glycol ether (e.g., an alkyl end capped glycolether) as opposed to being simply a glycol where R₁ is H. Typically, R₁is H for less than 90 percent, more typically less than 50 percent andeven possibly less than 30 percent or 20 percent by weight of the glycolcomponent, the overall fluid composition, or both. It will be understoodthat, as used herein, the term “polyglycol” refers to a glycol such asthat of EQUATION I in which n is at least 2 or greater. The term“glycol” is inclusive of all polyglycols. It should also be understoodthat the glycol component can include both those glycols in which R₁ isan alkyl group and those in which R₁ is H.

The glycol component can include an amount of glycol where n=1. Whenincluded, such glycol is less than about 5 percent by weight of theglycol component. Preferably, glycols of the glycol component compriseglycols (e.g., alkoxy glycols) where n=2, glycols (e.g., alkoxy glycols)where n=3, glycols (e.g., alkoxy glycols) where n=4 or more, or anymixture thereof. More preferable glycol components comprise a mixture ofglycols (e.g., alkoxy glycols) having n=2, n=3, and n=4 or more. It isalso preferred for the glycols wherein n=2 or more to be present in theglycol component and/or the overall functional fluid in an amount thatis at least about 50 percent by weight, more preferably at least about60 percent by weight and more preferably at least about 75 percent byweight of the glycol component, the overall functional fluid or both.The amount of glycol in which n is 2 or more is even more preferably atleast about 90 percent by weight.

It is also preferred for the glycols wherein n=2 or more to be presentin the glycol component and/or the overall functional fluid in an amountthat is no greater than about 99 percent by weight.

The glycols in which n=2 are preferably present in an amount that is atleast about 0.5 percent by weight of the total glycol component, morepreferably at least about 1 percent by weight of the total glycolcomponent, and even more preferably at least about 2 percent by weightof the total glycol component. The glycols in which n=2 are preferablypresent in an amount that is no greater than about 10 percent by weight,more preferably no greater than about 8 percent by weight, and even morepreferably no greater than about 7 percent by weight of the total glycolcomponent.

The glycols in which n=3 are preferably present in an amount that is nogreater than about 80 percent by weight of the total glycol component,more preferably no greater than about 70 percent by weight of the totalglycol component, and even more preferably no greater than about 66percent by weight of the total glycol component. The glycols in whichn=3 are preferably present in an amount that is at least about 40percent by weight, more preferably at least about 50 percent by weight,and even more preferably at least about 58 percent by weight of thetotal glycol component.

The glycols in which n=4 or greater are preferably present in an amountthat is no greater than about 45 percent by weight, more preferably nogreater than about 40 percent by weight, and even more preferably nogreater than about 35 percent by weight of the total glycol component.The glycols in which n=4 or greater are preferably present in an amountthat is at least about 15 percent by weight, more preferably at leastabout 20 percent by weight, and even more preferably at least about 25percent by weight of the total glycol component. Preferable glycolcomponents include an R₁ group comprising a methyl, an ethyl, a propyl,a butyl, or combinations thereof.

Without limitation, examples of useful glycols (e.g., alkoxy glycols orotherwise) include methoxy triglycol, methoxy diglycol, methoxytetraglycol, methoxy polyglycol (e.g., mixtures of methoxy triglycol,methoxy tetraglycol, and other glycols in which R₁ is CH₃ and n is 5 ormore), ethoxy triglycol, ethoxy diglycol, ethoxy tetraglycol, propoxytriglycol, butoxy triglycol (e.g., triethylene glycol monobutyl ether),butoxy diglycol (e.g., diethylene glycol monobutyl ether), butoxytetraglycol, butoxy polyglycol (e.g., mixtures of butoxy triglycol,butoxy tetraglycol, and other glycols in which R₁ is an alkyl having 4carbon atoms and n is 5 or greater), butoxy pentoxy diglycol, pentoxytriglycol, 2-ethylhexyl diglycol and any mixture thereof.

Preferable glycols (e.g., alkoxy glycols) of the glycol componentinclude, without limitation, methoxy triglycol, methoxy diglycol,methoxy polyglycol, methoxy tetraglycol, ethoxy polyglycol, ethoxytriglycol, ethoxy diglycol, ethoxy tetraglycol, butoxy polyglycol,butoxy triglycol, butoxy diglycol, butoxy tetraglycol, triethyleneglycol monohexyl ether, diethylene glycol monopropyl ether, triethyleneglycol monopropyl ether, dipropylene glycol monomethyl ether,dipropylene glycol monopropyl ether, tripropylene glycol monopropylether, dipropylene glycol monobutyl ether, tripropylene glycol monobutylether, polypropylene glycol monobutyl ether, polypropylene glycolmonopropyl ether, or mixtures thereof. More preferable alkoxy glycolcomponents comprise methoxy triglycol, methoxy diglycol, methoxypolyglycol, butoxy triglycol, butoxy diglycol, butoxy polyglycol,triethylene glycol monohexyl ether, diethylene glycol monopropyl ether,triethylene glycol monopropyl ether, dipropylene glycol monomethylether, dipropylene glycol monopropyl ether, tripropylene glycolmonopropyl ether, dipropylene glycol monobutyl ether, tripropyleneglycol monobutyl ether, polypropylene glycol monopropyl ether,polypropylene glycol monobutyl ether or mixtures thereof. Mostpreferable alkoxy glycol components comprise a mixture of two or more ofmethoxy polyglycol, butoxy diglycol, butoxy triglycol, butoxypolyglycol, triethylene glycol monopropyl ether, tripropylene glycolmonopropyl ether, tripropylene glycol monobutyl ether, polypropyleneglycol monopropyl ether, or polypropylene glycol monobutyl ether.

Further examples of useful glycols (e.g., alkoxy glycols or the like)include, without limitation, diethylene glycol monopropyl ether,triethylene glycol monopropyl ether, dipropylene glycol monomethylether, dipropylene glycol monopropyl ether, tripropylene glycolmonopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycolmonomethyl ether, tripropylene glycol monoethyl ether, tripropyleneglycol monopropyl ether, tripropylene glycol monobutyl ether,polypropylene glycol monopropyl ether, polypropylene glycol monobutylether, polybutylene glycol monopropyl ether, polybutylene glycolmonobutyl ether, combinations thereof or the like.

Without limitation, methods of preparing useful alkoxy glycols includean alkoxylation reaction that reacts an alkylene oxide with an alcoholto produce an alkoxy glycol.

The glycol component may also include a glycol polymer, which can be ahomopolymer, block copolymer, random copolymer or the like. Glycolcopolymers are preferred. Glycol copolymers will typically include oneor more first repeat units of EQUATION I having a first configurationand one or more second repeat units having a second configuration. Inparticular, the glycol copolymer typically includes at least one offirst repeat unit of EQUATION I wherein R₂, R₃, R₄, and R₅ are each H.The glycol copolymer also typically includes at least one second repeatunit wherein at least one and typically only one, but also possibly two,three or all four of R₂, R₃, R₄, and R₅ are each an alkyl groupcontaining 1 to 8 carbon atoms. Preferable second repeat units of theglycol copolymer include an R₂ or R₃ group and more preferably an R₄ orR₅ group comprising a methyl, an ethyl, a propyl, a butyl, orcombinations thereof. More preferable second repeat units of the glycolcopolymer include an R₂ or R₃ group and more preferably an R₄ or R₅group comprising a methyl or an ethyl group. Still more preferablesecond repeat units of the glycol copolymer include an R₂ or R₃ groupand more preferably an R₄ or R₅ group comprising a methyl group (i.e.,propylene oxide repeating units).

In one exemplary embodiment, the glycol polymer has the followingformula:

R₇—(O—(PO)_(m)(EO)_(n)—R₈)_(x)

-   -   wherein PO is a propylene oxide unit;    -   EO is ethylene oxide unit;    -   R₈ is a hydrogen or a hydrocarbyl group;    -   x is at least 1;    -   R₇ is a hydrogen or an x valent hydrocarbyl group;    -   m is a number of at least 0;    -   n is a number at of least 0; and    -   m+n is greater than 0.

The glycol polymer has a molecular weight that is at least about 500g/mol, preferably at least about 750 g/mol, and more preferably at leastabout 900 g/mol. The glycol polymer has a molecular weight that is nogreater than about 2,000 g/mol, more preferably no greater than about1,500 g/mol, and even more preferably no greater than about 1,110 g/mol.

In accordance with one exemplary embodiment of a glycol copolymer, m andn are equal, in which case the glycol copolymer contains equal amountsof ethylene oxide and propylene oxide repeating units. The number ofrepeating ethylene oxide units and the number of propylene oxide unitsare each preferably greater than 2, more preferably greater than 4, andeven more preferably greater than 8. One suitable glycol copolymer isUCON® 50 HB-260 (The Dow Chemical Company). UCON 50 HB-260 comprisesequal numbers of propylene oxide and ethylene oxide units and has amolecular weight of about 1,000 g/mol. In UCON 50 HB-260, R₇ is aunivalent alkyl group, x is 1, and R₈ is a hydrogen atom.

When utilized, the glycol borate ester component preferably includes atleast one ingredient having the formula:

with repeat unit:

wherein R₁, R₂, R₃, R₄, and R₅ can be any of groups as specified withrespect to EQUATION I and n can be as specified with respect to EQUATIONI. As such, the glycol borate ester component can have any of the repeatunits of glycol component as discussed with respect to EQUATION Iherein. It is also understood that the glycol borate ester component andany borate containing compound is not considered as part of the glycolcomponent, but rather is separate.

Examples of optional glycol borate ester components include alkoxyglycol borate ester components such as methoxy triethylene glycol borateester, ethoxy triethylene glycol borate ester, butoxy triethylene glycolborate ester and mixtures thereof disclosed in U.S. Pat. No. 6,558,569,hereby incorporated by reference. If a borate ester component is presentin the composition, it is preferably present in an amount greater thanabout 1 percent by weight of the functional fluid. The optional borateester is also preferably present in an amount that is less than about 10percent by weight and more preferably less than about 4 percent byweight of the functional fluid. In one embodiment, the functional fluidcomposition is substantially free (less than about 0.5 percent by weightof the functional fluid) or entirely free of any borate ester component.

When a glycol borate ester component is included in the composition, itis typically the case that the glycol groups of the component representa substantial portion of the overall composition. Such glycol groups, asdefined herein, are the portions of EQUATION I and EQUATION II attachedto the (H) hydrogen atom or the (B) Boron atom of those equations. Thus,such glycol groups are as follows:

These glycol groups can represent at least about 50 percent, moretypically at least about 60 percent, still more typically at least about80 percent and even possibly at least about 90 percent by weight of theoverall composition.

As mentioned above, the functional fluids of the present disclosure alsoinclude an additive package which contains at least one fatty acid, atleast one phosphate ester, one or more corrosion inhibitors, and one ormore of the following: an antifoaming agent, a pH stabilizer, achelating agent, and an antioxidant. The corrosion inhibitors in theadditive package preferably include compounds that inhibit the corrosionof tinned iron, steel, aluminum, cast iron, brass, and copper, each ofwhich has a corrosion specification set forth in SAE J1703, SAE J1704and FMVSS 116. However, in an especially preferred embodiment, thecorrosion inhibitors also include one or more compounds that inhibit thecorrosion of zinc.

The additive package is preferably present in an amount that is at leastabout 0.1 percent by weight of the fluid composition, more preferably atleast about 0.2 percent by weight of the fluid composition, and mostpreferably at least about 0.3 percent by weight of the fluidcomposition. The additive package is preferably present in an amountthat is no greater than about 10 percent by weight of the fluidcomposition, more preferably no greater than about 6.0 percent by weightof the fluid composition, and most preferably no greater than about 4.0percent by weight of the fluid composition.

The fatty acids in the additive package preferably include one or morealiphatic carboxylic acids having at least 2, preferably at least 5,more preferably at least 10, and even more preferably at least 15 carbonatoms. The aliphatic carboxylic acids generally have no more than 35,preferably no more than 30, and more preferably no more than 25 carbonatoms. Straight chain, monofunctional fatty acids are preferred, andstraight chain, unsaturated, monofunctional fatty acids are morepreferred. Monounsaturated fatty acids are especially preferred.Suitable fatty acids include without limitation, oleic acid, palmiticacid, stearic acid, myristic acid, palmitoleic acid, elaidic acid, andlinoleic acid. The fatty acids in the additive package are generallypresent in an amount that is at least about 0.01 percent, preferably atleast about 0.04 percent, and more preferably at least about 0.08percent by weight of the fluid composition. The fatty acids aregenerally present in an amount that is no greater than about 0.4percent, more preferably no greater than about 0.2 percent, and mostpreferably no greater than about 0.15 percent by weight of the fluidcomposition.

One or more of the additives in the additive package will generally be aphosphate, and more specifically, a phosphate ester. The phosphate esteris generally a mono, di- or tri-ester of an alcohol and phosphoric acid(H₃PO₄). The alcohol preferably has the following formula:

R₁—R₂—OH   EQUATION III

wherein R₁ is a substituted or unsubstituted alkyl, alkenyl, or arylgroup having at least 2, more preferably at least 3, even morepreferably at least 4, and still more preferably at least 6 carbonatoms. R₁ preferably has no more than 30, more preferably no more than28, even more preferably no more than 26, and still more preferably nomore then 24 carbon atoms. R₂ is preferably an alkyl or alkoxy grouphaving from two to six carbon atoms. In one exemplary embodiment, R₂ isan ethoxy group (—O—CH₂—CH₂—), Suitable phosphate esters include withoutlimitation, RHODOFAC® RM-510 (Rhodia), a dinonylphenol, ethoxylated,phosphate ester, LUBRHOPHOS® LP-700 (Rhodia), a phosphate ester ofethoxylated phenol, LUBRHOPHOS® LB-400 (Rhodia), an ethoxylatedphosphate ester of oleic alcohol, LUBRHOPHOS® LK-500 (Rhodia), aphosphate ester of ethoxylated hexanol, and tricresyl phosphate, aphosphate triester of cresol.

The phosphate ester is preferably present in an amount that is at leastabout 0.05 percent, more preferably at least about 0.1 percent, and evenmore preferably at least about 0.15 percent by weight of the functionalfluid. The phosphate ester is preferably present in an amount that is nogreater than about 0.4 percent, more preferably no greater than about0.3 percent, and even more preferably no greater than about 0.25 percentby weight of the functional fluid. Without wishing to be bound by anytheory, and as explained further below, it is believed that thecombination of the phosphate ester and the fatty acid in the functionalfluid additive package produces a synergistic effect that unexpectedlyimproves the lubricity of the functional fluid.

The corrosion inhibitors preferably include at least one heterocyclicnitrogen-containing compound, for example, triazoles such asbenzotriazole, tolytriazole, 1, 2, 4 triazole, and mixtures thereof. Thetriazole compounds are preferably present in an amount that is at leastabout 0.01 percent, more preferably at least about 0.05 percent, andmost preferably at least about 0.09 percent by weight of the total fluidweight. The triazole compounds are preferably present in an amount thatis no greater than about 0.4 percent, more preferably no greater thanabout 0.3 percent, and most preferably no greater than about 0.20percent by weight of the total fluid composition. Without wishing to bebound by any theory, triazole compounds such as benzotriazole,tolytriazole, and 1, 2, 4 triazole are believed to be particularlyeffective for inhibiting copper corrosion.

The corrosion inhibitors also preferably include amine compounds otherthan triazoles, including alkyl amines (e.g., di n-butylamine and din-amylamine), cyclohexylamine, piperazines (e.g., hydroxylethylpiperazine), and salts thereof. Non-triazole amine compounds which areparticularly useful as corrosion inhibitors in the functional fluidcompositions of the present disclosure include the alkanol amines,preferably those containing one to three alkanol groups with eachalkanol group containing from one to six carbon atoms. Examples ofuseful alkanol amines include mono-, di- and trimethanolamine, mono-,di- and triethanolamine, mono-, di- and tripropanolamine and mono-, di-and triisopropanolamine. Preferred alkanol amines include butyldiethanolamine and diisopropanolamine (“dipa”). Without wishing to be bound byany theory, the alkanolamines are believed to be effective forinhibiting the corrosion of ferrous compounds (e.g., iron, steel) andalso act as a buffer.

The non-triazole amine compounds are preferably present in an amountthat is at least about 0.1 percent, more preferably at least about 0.5percent, and even more preferably at least about 0.8 percent by weightof the fluid composition. The non-triazole amine compounds arepreferably present in an amount that is no greater than about 3 percent,more preferably no greater than about 2.0 percent, and most preferablyno greater than about 1.5 percent by weight of the total fluidcomposition.

The corrosion inhibitors may include one or more alkenyl succinicanhydrides. Preferred alkenyl succinic anhydrides include derivatives ofmaleic anhydride. Dodecenyl succinic anhydride is especially preferred.When included in the functional fluid, the alkenyl succinic anhydridesare preferably present in an amount that is at least about 0.1 percent,more preferably at least about 0.12 percent, and most preferably atleast about 0.14 percent by weight of the functional fluid composition.The alkenyl succinic anhydrides are preferably present in an amount thatis no greater than about 0.5 percent, more preferably no greater thanabout 0.3 percent, and most preferably no greater than about 0.2 percentby weight of the functional fluid composition.

In certain preferred embodiments, the corrosion inhibitors also includeone or more inorganic nitrates, preferably sodium nitrate. The inorganicnitrates are preferably present in an amount that is at least about 0.01percent, more preferably at least about 0.015 percent and mostpreferably at least about 0.02 percent by weight of the fluidcomposition. The inorganic nitrates are preferably present in an amountthat is no greater than about 0.06 percent, more preferably no greaterthan about 0.05 percent, and most preferably no greater than about 0.04percent by weight of the fluid composition. Without wishing to be boundby any theory, the inorganic nitrates are believed to be effective atinhibiting the corrosion of aluminum.

The corrosion inhibitors may include one or more inorganic borates suchas Sodium Tetraborate, commonly known as Borax. The inorganic boratesare preferably provided as solid hydrates. An especially preferredinorganic borate is sodium tetraborate pentahydrate Na₂B₄O₇.5H₂O, alsoknown as Borax 5 Mol. Another exemplary inorganic borate is sodiumtetraborate decahydrate (Na₂B₄O₇.10H₂O). When present, the inorganicborate is preferably provided in an amount that is at least about 0.03percent, more preferably at least about 0.05 percent, and mostpreferably at least about 0.07 percent by weight of the fluidcomposition. The inorganic borate is preferably provided in an amountthat is no greater than about 0.1 percent, more preferably greater thanabout 0.09 percent, and most preferably no greater than about 0.08percent by weight of the fluid composition. Without wishing to be boundby any theory, the inorganic borates are believed to be effective atinhibiting ferrous corrosion (e.g., iron and steel).

The corrosion inhibitors may also optionally include one or moresilicone compounds such as silicate esters. Preferred silicate estersinclude polymers of dialkoxysiloxanes, including without limitationpoly(diethoxysiloxane) (e.g., PSI-021). The silicone corrosion inhibitoris preferably provided in an amount that is at least about 0.001percent, more preferably at least about 0.003 percent, and mostpreferably at least about 0.004 percent by weight of the fluidcomposition. The silicone corrosion inhibitor is preferably provided inan amount that is no greater than about 0.008 percent, more preferablyno greater than about 0.007 percent, and most preferably no greater thanabout 0.006 percent by weight of the fluid composition. Without wishingto be bound by any theory, the silicone corrosion inhibitors arebelieved to inhibit the corrosion of brass and aluminum.

In addition to the foregoing corrosion inhibitors, the functional fluidadditive package may also include other additive compounds such asantifoaming agents, pH stabilizers, chelating agents, antioxidants, andthe like. Preferred antifoaming agents include poly(dimethylsiloxane)and silicone-based compounds such as SAG 100 Antifoam, a product of GEAdvanced Materials. If present, the antifoaming agent is preferablyprovided in an amount that is no greater than about 0.00020 percent andmore preferably no greater than about 0.00015 percent by weight of thefluid composition. The antifoaming agent is preferably present in anamount that is at least about 0.00001 percent and more preferably atleast about 0.00005 percent by weight of the fluid composition.

Suitable antioxidants include phenolic compounds and quinolinecompounds. Exemplary phenolic antioxidants include BHT (butylatedhydroxytoluene); 2,6-di-tert-butyl-4-methyl phenol (which is supplied byGreat Lakes Chemical Corporation under the name Lowinox® 624)2,6-di-tert-butyl-p-cresol), 2,6-di-tertiary-butyl-4-sec-butylphenol(which is supplied by the SI Group under the name Isonox® 132), andbisphenol A. Exemplary quinoline antioxidants include Agerite® Resin D,a polymerized trimethyl dihydroquinoline compound supplied by the R.T.Vanderbilt Company. If antioxidants are included in the additivepackage, they are preferably provided in an amount that is at leastabout 0.1 percent, more preferably at least about 0.2 percent, and mostpreferably at least about 0.25 percent by weight of the fluidcomposition. The antioxidants are provided in an amount that ispreferably no greater than about 1.0 percent, more preferably no greaterthan about 0.8 percent, and most preferably no greater than about 0.4percent by weight of the fluid composition.

Suitable chelating agents include trioctylphosphine oxide,tributyl-phosphate, dibuty butyllphosphate, DEHPA(Di(2-ethylhexyl)phosphoric acid) and propanediamine/xylene compositionssuch as Dupont Metal Deactivator (N,N′ Disalicylidene-1,2-propanediameneand xylene). When used, the chelating agents are preferably present inan amount that is at least about 0.01 percent, more preferably at leastabout 0.05 percent, and most preferably at least about 0.08 percent byweight. The chelating agents are preferably present in an amount that isno greater than about 0.2 percent, most preferably no greater than about0.15 percent, and most preferably no greater than about 0.13 percent byweight of the fluid composition.

As mentioned above, SAE J1703 and J1704 set forth corrosion standardsfor DOT 3 and DOT 4 brake fluids, respectively. In accordance with bothstandards, two sets of six specified metal corrosion test strips arepolished, cleaned and weighed. The six metal strips comprising each setare fastened together at one end. Each strip is approximately 8 cm long,1.3 cm wide, not more than 0.6 mm thick, and has a surface area of 25±5cm². The specified metals are copper, brass, cast iron, aluminum, steel,and tinned iron. Two styrene-butadiene rubber (“SBR”) cups are providedas set forth in Section 7.6 of FMVSS 116 and Appendices C and D of SAEJ1704 (Rev. April 2004), and their base diameters are measured. Inaddition, the cups' International Rubber Hardness Degree (“IRHD”) valuesare determined using the ASTM D1415 test method, the entirety of whichis incorporated herein by reference. The two SBR cups and two metalstrip assemblies are placed in a jar containing the brake fluid and five(5) percent water (by volume) with the metal strip assemblies each beingplaced in one of the respective cups. The jar is capped and placed in anoven at 100° C. for 120 hours. The strips are then removed anddesiccated at 23° C.±2° C. for 1 hour. Following desiccation, the stripsand are each weighed to the nearest 0.1 mg and the change in weight iscalculated for each strip. The area of the strips is then determined,and the weight change per unit area in mg/cm² of surface area iscalculated. The diameter and IRHD values of the cups are thendetermined. According to FMVSS 116, in order to be certified as a DOT 4brake fluid, the weight change per unit surface area must not exceed thefollowing specifications, which are identical to those of SAE J1703 andJ1704:

TABLE 2 Maximum weight Test Strip Material change in mg/cm² Steel,tinned iron, cast iron 0.2 Aluminum 0.1 Brass, Copper 0.4

In addition, the SBR cup specification of FMVSS 116 calls for an innercup diameter increase of no more than 1.4mm and a hardness decrease ofno more than 15 International Rubber Hardness Degrees. The SAE J1704specifications are identical, except that they call for an SBR Cupvolume increase of no more than 16 percent instead of specifying adiameter increase. In addition, SAE J1703 and J1704 call for a pH of notless than 7.0 and not more than 11.5 when the functional fluid is mixedwith an equal volume of a 50 percent ethanol/50 percent distilled watermixture neutralized to a pH of 7.0. The standards also call for asediment level of not more than 0.1 percent by volume. Each standardalso includes a low temperature appearance requirement that calls forthe absence of stratification, sedimentation, or crystallization underspecified test conditions.

As mentioned above, it has been proposed to modify the brake fluid/watercomposition used to perform the SAE J1703 and SAE J1704 test proceduresin order to better simulate the environments to which many brake fluidsare subjected. In particular, many localities use road salt to keeproads free of ice and snow during the winter months. As a result, thebrake fluid frequently becomes contaminated with water/salt solutionswhich can degrade the brake fluid's performance. In one preferredembodiment, when the functional fluids of the present disclosure aresubjected to the J1703/J1704 corrosion test using a mixture of brakefluid with 5 percent water (by volume) and 25 ppm chloride ion, themixture meets the J1703/J1704 and FMVSS 116 corrosion specifications forthe maximum allowable weight change per surface area for tinned iron,steel, aluminum, cast iron, brass and copper.

In addition to their corrosion inhibition properties, the fluidcompositions of the present disclosure exhibit superior water stabilityand are able to maintain high boiling points and low viscosities atrelatively high water levels. In certain preferred embodiments, thefluid compositions maintain a wet equilibrium reflux boiling point(WERBP) of no less than about 140° C., preferably no less than about150° C., more preferably no less than about 200° C., and even morepreferably no less than about 220° C. In certain preferred embodiments,the fluid compositions maintain a dry equilibrium reflux boiling point(ERBP) of no less than about 200° C., preferably no less than about 220°C., more preferably no less than about 230° C. and even more preferablyno less than about 240° C. The functional fluids preferably have akinematic viscosity at −40° C. of no greater than about 1800 cSt, morepreferably no greater than about 1400 cSt, and most preferably nogreater than about 1000 cSt.

EXAMPLES Example 1 Corrosion and Lubricity Performance of a FunctionalFluid with a Phosphate Ester and with a Phosphate Ester/Oleic acidCombination

Lubricity and corrosion test data are obtained for a commerciallyavailable DOT 3 brake fluid (PM6664) base fluid and two modifiedversions of the fluid containing a RHODOFAC® RM 510 phosphate ester. Inone of the modified versions of the fluid, the phosphate ester iscombined with a fatty acid (oleic acid) and in the other version nofatty acid is included. The formulations are as follows:

TABLE 3 LV RG1 LV RG2 (Added (Added PM6664 phosphate phosphate esterBase fluid ester) and oleic acid) Component Wt. % Wt. % Wt. % ButylCARBITOL ® Solvent 2.9 2.9 2.9 LG (Butoxy diethylene glycol) Methoxytriethylene glycol 53.15 52.53 52.43 Butoxy triethylene glycol 9.0 10.9410.94 Methoxy polyglcyol¹ 12.0 12.0 12.0 UCON ® 50 HB 260 20.0 20.0 20.0CARBITOL ® solvent low 0.72 gravity Monoethylene glycol 0.2 SodiumNitrate 0.02 0.03 0.03 Propylene glycol (used in 0.5192 inhibitorpackage) Borax 5 Mol 0.071 Dodecenyl succinic 0.15 anhydride Di (2-ethylhexyl) 0.1 phosphoric acid Dupont Metal Deactivator 0.01 SiliconCorrosion Inhibitor 0.005 PSI-21 Hydroxyethyl piperazine 0.5 Oleic acid0.10 Isonox 132 0.3 0.3 Tolytriazole 0.05 0.05 1,2,4 triazole 0.05 0.05Rhodafac RM 510 0.20 0.20 Diisopropanol amine 1.0 1.0 Total 100.0 100.0100.0

In Table 3, “Methoxy polyglycol” (“MPG”) refers to a mixture of methoxytriethylene glycol (10 wt. percent of the MPG) methoxy tetraethyleneglycol (78.4 wt. percent of the MPG), and methoxy poly glycols with fiveor more repeating ethylene glycol units (10.9 wt. percent of the MPG).The LV-RG1 and LV-RG2 formulations have the following equilibrium refluxboiling points and viscosities:

TABLE 4 LV-RG1 LV-RG2 ERBP (° C.) 253 255 WERBP 146 146 −40° C.kinematic viscosity (cSt) 835.6 846.6

Each of the foregoing fluids are tested for corrosion inhibition usingthe SAE J1703 and J1704 test protocols both with and without theaddition of 25 ppm chloride ion to the water that is mixed with thefunctional fluid. The results are as follows:

TABLE 5 Mass Change mg/cm² Fluid Tinned Iron Steel Aluminum Cast IronBrass Copper Zinc LV-RG1 0.0094 0.0164 0.0163 0.0175 0.0242 0.0040 N/A(0 ppm CI) LV-RG2 0.0000 0.0164 0.0000 0.0455 0.0081 0.0000 N/A (0 ppmCI) LV-RG1 0.0094 0.0041 0.0122 0.0070 0.0242 −0.0523 0.0653 (25 ppm CI)LV-RG 2 0.0000 0.0206 0.0163 0.0105 0.0000 −0.0886 0.0653 (25 ppm CI)

TABLE 6 Change in Change in SBR Cup SBR Cup Diameter Hardness Fluid pHSediment Fluid (mm) (IRHD) appearance after (vol. %) LV-RG1 0.2075−4.235 Pass 9.02 <0.05 (0 ppm Cl) LV-RG2 0.305 −4.675 Pass 8.92 <0.05 (0ppm Cl) LV-RG1 0.1325 −4.175 Pass 9.01 <0.05 (25 ppm Cl) LV-RG2 0.13−3.475 Pass 8.88 <0.05 (25 ppm Cl)

The functional fluids in Table 3 are also tested for lubricity using aCameron-Plint Reciprocating Sliding Wear Tester in which an upperspecimen comprising an 80 Durometer EPDM rubber is oscillated against alower specimen comprising a DuPont ZYTEL®70G43 nylon 66 resin reinforcedwith 43 percent by weight glass fibers. The results are presented inFIG. 1 which plots the coefficient of friction versus time. As FIG. 1indicates, both the LV-RG1 and LV-RG2 fluids achieve better lubricities(i.e., lower coefficients of friction) than the base PM6664 materialafter about 90 seconds. As indicated above, unlike PM 6664, both theLV-RG1 and LV-RG2 fluids include a phosphate ester. However, LV-RG2 alsoincludes oleic acid. As FIG. 1 indicates, combining oleic acid and aphosphate ester produces more than a two-fold improvement in lubricityand a more consistent lubricity over the testing period. As Table 4indicates, both LV-RG1 and LV-RG2 meet the ERBP specifications of bothSAE J1703 (ERBP not less than 230° C.) and SAE J1704 (ERBP of not lessthan 205° C.). They also meet the −40° C. kinematic viscosityspecifications of both standards (not more than 1800 cSt) and the WERBPspecification of SAE J1703 (not less than 140° C.). In addition, evenwith the addition of 25 ppm chloride ion, both LV-RG1 and LV-RG2 meetthe tinned iron, steel, aluminum, cast iron, brass, and copper corrosionspecifications of both SAE J1703 and J1704 as well as the hardness andrubber cup diameter specifications of both standards.

Example 2 Corrosion and Lubricity Performance of a Functional Fluid withVarying Amounts of a Phosphate Ester and without a Fatty Acid

In this example, lubricity and corrosion data are obtained for acommercial DOT 3 brake fluid (DBF 310 GC) and two modified versions ofthe fluid in which varying amounts of RHODOFAC® RM-510 (a dialkyl phenolethoxylated phosphate ester) are added. The formulations are provided inTable 7:

TABLE 7 DBF 310 GC + DBF 310 GC + 0.2% RM- DBF 310 GC 0.1% RM-510 510Component (Wt. %) (Wt. %) (Wt. %) Butoxy triethylene glycol 18.5 18.518.5 Butoxy polyethylene 10.0 10.0 10.0 glycol Ethoxy triethylene glycol18.1 18.1 18.0 Methoxy triethylene 14.0 14.0 14.0 glycol Methoxypolyethylene 7.0 7.0 7.0 glycol Butyl Carbitol (Butoxy 3.0 3.0 3.0Diethylene Glycol) Diflash refined 14.0 14.0 14.0 Di-Diisopropanol amine1.0 1.0 1.0 (“DIPA”) Isonox 0.30 0.30 0.30 Tolytriazole 0.05 0.05 0.051,2,4 triazole 0.05 0.05 0.05 Sodium Nitrate 0.03 0.03 0.03 PusherRefined 14.0 14.0 14.0 SAG 100 Antifoam 0.0001 0.0001 0.0001 RhodafacRM-510 0.10 0.20 Total 100.0 100.0 100.0

In Table 7, “butoxy polyethylene glycol” (“BPG”) refers to a mixture ofbutoxy triethylene glycol (11.9 wt. percent of the BPG), butoxytetraethylene glycol (64.2 wt. percent of the BPG) and butoxypolyethylene glycols with 5 or more repeating ethylene oxide units (21.9wt. percent of the BPG). “Diflash refined” refers to a mixture ofdiethylene glycol (22.8 wt. percent of the Diflash), triethylene glycol(58.3 wt. percent of the Diflash), tetraethylene glycol (16.4 wt.percent of the Diflash), and ethylene glycols with 5 or more repeatingethylene oxide units (1.8 wt. percent of the Diflash). “Pusher refined”refers to a mixture of tetraethylene glycol (65.3 wt. percent of thePusher), pentaethylene glycol (29.2 wt. percent of the Pusher),hexaethylene glycol (1.8 wt. percent of the Pusher), and ethyleneglycols with 7 or more repeating ethylene oxide units (2.3 wt. percentof the Pusher).

The fluids in Table 7 are subjected to the SAE J1703/J1704 and FMVSS 116corrosion tests both with and without the addition of 25 ppm chlorideion to the water that is added to the functional fluid. The results areset forth below in Tables 8 and 9:

TABLE 8 Mass Change mg/cm² Tinned Fluid Iron Steel Aluminum Cast IronBrass Copper Zinc DBF 310 −0.0938 0.0041 0.0163 0.0070 −0.0404 −0.06440.0490 GC (25 ppm CI) DBF 310 −0.0047 0.0041 0.0163 0.0210 0.0121−0.0483 0.0612 GC + 0.1% RM- 510 (25 ppm CI) DBF 310 −0.0094 0.00000.0082 0.0105 −0.0162 −0.0362 N/A GC + 0.1% RM- 510 (0 ppm CI) DBF 310−0.0047 0.0082 0.0286 0.0350 0.0202 −0.0888 0.0776 GC + 0.2% RM- 510 (25ppm CI DBF 310 0.0000 0.0123 0.0122 0.0280 −0.0040 −0.0322 N/A GC + 0.2%RM- 510 (0 ppm CI)

TABLE 9 Change in SBR Cup Change in SBR Diameter Cup Hardness pHSediment Fluid (mm) (IRHD) After (vol. %) DBF 310 GC 0.1 −1.6 9.46 none(25 ppm Cl) DBF 310 GC + 0.0475 −1.325 9.38 0.05 0.1% RM-510 (25 ppm Cl)DBF 310 GC + 0.065 −1.375 9.34 none 0.1% RM-510 (0 ppm Cl) DBF 310 GC +0.0275 −0.6 9.24 none 0.2% RM-510 (25 ppm Cl) DBF 310 GC + 0.075 −2.0259.14 none 0.2% RM-510 (0 ppm Cl)

As Tables 8 and 9 indicate, both the 0.1 percent RM-510 and 0.2 percentRM-510 formulations meet the SAE J1703/1704 corrosion specifications fortinned iron, steel, aluminum, cast iron, brass, and copper as well asthe rubber cup diameter and hardness specifications of those standards.

The functional fluids of Table 7 are also tested for lubricity using theCameron-Plint device as described previously with respect to Example 1.The surfaces used with the Cameron-Plint device are those used inExample 1. The resulting lubricity data is presented in FIG. 2. As thefigure indicates, the addition of 0.1 percent of RM-510 provides forgreater lubricity from 10 seconds to about 230 seconds. However, afterabout 230 seconds, the 0.1 percent RM-510 formulation experiences adecrease in lubricity. In contrast, the formulation with 0.2 percentRM-510 maintains a coefficient of friction below about 0.06 throughoutthe test period. Both formulations in Table 7 include a phosphate ester(RM-510), but neither of them includes a fatty acid. In contrast, theLV-RG2 formulation of Table 3 includes both a fatty acid and a phosphateester. A comparison of FIGS. 1 and 2 indicates that the combination ofoleic acid and RM-510 produces a substantial increase in lubricity evenwhen the amount of RM-510 remains constant, further indicating that thecombination of a fatty acid and a phosphate ester achieves a synergisticaffect and an unexpected improvement in lubricity.

Functional fluids of the present disclosure are well suited for use as ahydraulic fluid for numerous mechanical systems (e.g., hydraulic lifts,cranes, forklifts, bulldozers, hydraulic jacks, brake systems,combinations thereof, or the like). The high lubricity as well as theERBP, WERBP, and low temperature viscosity of these fluid compositionsmake them well-suited for brake systems in transportation vehicles(e.g., fixed and rotary wing aircraft, trains, automobiles in classes 1to 8, or the like). These braking systems include anti-lock brakingsystems (ABS), stability control systems, or combinations thereof.

In one exemplary implementation, a brake system is provided whichcomprises a depressible actuator, a master cylinder, a piston, and arubber cup seal disposed on the piston. The functional fluid of thepresent disclosure is disposed in the bore of a master cylinder and isused to transmit pressure to a braking mechanism (e.g., brake pad androtor) to slow or stop the vehicle. As the actuator is depressed, thepiston moves along the interior of the master cylinder and displacesfluid from the cylinder bore. During this operation, the rubber cupfrictionally engages the walls of the master cylinder which caneventually cause the rubber cup to wear, leading to leakage around therubber cup and diminished braking performance. In certain exemplaryapplications, the master cylinder is lined with plastic, and thefunctional fluid lubricates the frictional engagement of the rubber cupand the plastic master cylinder lining. As illustrated in FIGS. 1 and 2,the use of a functional fluid comprising at least one glycol and anadditive package comprising at least one fatty acid and at least onephosphate ester beneficially reduces the amount of friction betweenrubber and plastic surfaces, thereby reducing the degree of wearexperienced by the rubber cup.

It will be further appreciated that functions or structures of aplurality of components or steps may be combined into a single componentor step, or the functions or structures of one-step or component may besplit among plural steps or components. The present disclosurecontemplates all of these combinations. Unless stated otherwise,dimensions and geometries of the various structures depicted herein arenot intended to be restrictive of the disclosure, and other dimensionsor geometries are possible. Plural structural components or steps can beprovided by a single integrated structure or step. Alternatively, asingle integrated structure or step might be divided into separateplural components or steps. In addition, while a feature of the presentdisclosure may have been described in the context of only one of theillustrated embodiments, such feature may be combined with one or moreother features of other embodiments, for any given application. It willalso be appreciated from the above that the fabrication of the uniquestructures herein and the operation thereof also constitute methods inaccordance with the present disclosure.

The explanations and illustrations presented herein are intended toacquaint others skilled in the art with the disclosure, its principles,and its practical application. Those skilled in the art may adapt andapply the disclosure in its numerous forms, as may be best suited to therequirements of a particular use. Accordingly, the specific embodimentsof the present disclosure as set forth are not intended as beingexhaustive or limiting. The scope of the disclosure should, therefore,be determined not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. Thedisclosures of all articles and references, including patentapplications and publications, are incorporated by reference for allpurposes.

1. A fluid composition, comprising: at least one glycol; and an additive package including at least one fatty acid and a phosphate ester wherein the at least one glycol is present in an amount that is greater than about 20 percent by weight of the total fluid composition.
 2. (canceled)
 3. (canceled)
 4. A fluid composition in accordance with claim 1, 3, wherein the at least one glycol has the formula:

wherein R₁, R₂, R₃, R₄, and R₅ are independently selected from the group consisting of hydrogen and an alkyl group containing 1 to 8 carbon atoms, and n is at least
 1. 5. The fluid composition of claim 4, wherein the at least one glycol comprises a first glycol component in which n=2 and a second glycol component in which n=3.
 6. A fluid composition in accordance with claim 4, wherein the at least one glycol component comprises a first glycol component in which R₁ is an alkyl group containing 1 carbon atom and a second glycol component in which R₁ is an alkyl group containing 4 carbon atoms.
 7. A fluid composition in accordance with claim 1, further comprising at least one glycol borate ester present in an amount that is less than about 70 percent by weight of the fluid composition.
 8. (canceled)
 9. (canceled)
 10. A fluid composition in accordance with claim 1, 9, wherein the at least one fatty acid is linear.
 11. A fluid composition in accordance with claim 1, wherein the at least one fatty acid is monounsaturated.
 12. (canceled)
 13. (canceled)
 14. A fluid composition in accordance with claim 1, wherein the phosphate ester is a phosphate ester of an alcohol having a formula R₁—R₂—OH, wherein R₁ is selected from the group consisting of a substituted or unsubstituted alkyl, alkenyl, and aryl group, and R₂ is selected from the group consisting of an alkyl group and an alkoxy group.
 15. The fluid composition of claim 14, wherein R₁ has at least 2 carbon atoms.
 16. (canceled)
 17. A fluid composition in accordance with claim 14, wherein R₁ is an alkyl-substituted aryl group.
 18. A fluid composition in accordance with claim 14, wherein R₂ is an ethoxy group.
 19. A fluid composition in accordance with claim 14, wherein R₁ is an unsubstituted alkenyl group.
 20. (canceled)
 21. (canceled)
 22. A fluid composition in accordance with claim 1, further comprising a polyalkylene glycol having the formula: R₇—(O—(PO)_(m)(EO)_(n)—R₈)_(x) wherein PO is a propylene oxide unit; EO is an ethylene oxide unit; R₇ is a hydrogen or an x-valent hydrocarbyl group; x is at least 1; R₈ is a hydrogen or a hydrocarbyl group; m is a number of at least 0; n is a number at of least 0; and m+n is greater than
 0. 23. (canceled)
 24. (canceled)
 25. (canceled)
 26. (canceled)
 27. (canceled)
 28. (canceled)
 29. (canceled)
 30. (canceled)
 31. A fluid composition comprising at least one glycol and an additive package, wherein when the fluid composition is applied between a first surface comprising a composite of al polyamide 66 and b) 43 percent by weight glass fiber and a second surface comprising an EPDM rubber having a shore A hardness of 80, and the first surface slidably engages the second surface, the coefficient of friction is less than about 0.07 after 100 seconds of sliding engagement between the first and second surfaces.
 32. The fluid composition of claim 31, wherein the coefficient of friction is less than about 0.03 after 100 seconds of sliding engagement between the first and second surfaces.
 33. (canceled)
 34. (canceled)
 35. (canceled)
 36. A fluid composition in accordance with claim 31, wherein the at least one glycol has the formula:

wherein R₁, R₂, R₃, R₄, and R₅ are independently selected from the group consisting of hydrogen and an alkyl group containing 1 to 8 carbon atoms, and n is at least
 1. 37. The fluid composition of claim 36, wherein the at least one glycol comprises a first glycol component in which n=2 and a second glycol component in which n=3.
 38. A fluid composition in accordance with claim 36, wherein the at least one glycol component comprises a first glycol component in which R₁ is an alkyl group containing 1 carbon atom and a second glycol component in which R₁ is an alkyl group containing 4 carbon atoms.
 39. A fluid composition in accordance with claim 31, further comprising at least one glycol borate ester present in an amount that is not greater than about 70 percent by weight of the fluid composition.
 40. A fluid composition in accordance with claim 31, further comprising at least one polyalkylene glycol having the formula: R₇—(O—(PO)_(m)(EO)_(n)—R₈)_(x) wherein PO is a propylene oxide unit; EO is an ethylene oxide unit; R₈ is hydrogen or a hydrocarbyl group; x is at least 1; R₇ is hydrogen or an x valent hydrocarbyl group; m is a number of at least 0; n is a number at of least 0; and m+n is greater than
 0. 41. (canceled)
 42. (canceled)
 43. (canceled)
 44. (canceled)
 45. (canceled) 